Energy necessary to suspend particles equals the energy dissipated by the particle moving at its terminal velocity in a still fluid

In a turbulent fluid, the settling velocity of a particle is different from that in a still fluid. Very simple model, unable to precisely predict Assumptions are more likely similar to homogenous suspension rather than just-suspended conditions

Cannot describe the effect of viscosity nor the effect of solid concentration. Cannot describe why the impeller that creates mass circulations (PBT) is more effective for suspending particles than impeller which creates a lot of turbulence

Same concept as Baldi et al. [13], solid particles are picked up by different sizes of eddies

Cannot describe the effect of viscosity nor the effect of solid concentration Cannot describe why the impeller that creates mass circulations (PBT) is more effective for suspending particles than impeller which creates a lot of turbulence

Proposed a model for estimation necessary conditions for incipient motion of solid particles based on average velocity of the liquid near the bottom of the vessel and forces acting on particles, like lift, drag, buoyancy, and weight resting at the bottom of the vessel

Model does not need any experimental adjustment, but the parameter describing solid arrangement is unknown

Power input dissipated by two phenomena: consumption of power to avoid settling and generating discharge flow for suspension

Values for calculated by this method are highly underpredicted compared to experimental data. This could be because the correlations for fluctuating velocity at the bottom of the vessel are not accurate